The low cost method of choice for copying a source medium is light lens xerography. Light lens xerography is a well known process by which a source medium is flood illuminated or scanned with light and the reflections therefrom are imaged via a copy lens assembly to a charged photoconductive medium, which is then discharged onto an output medium in accordance with the image formed on the source medium. A characteristic of the light lens xerographic process is that the image on the source medium and the resultant copying medium are either identical or are scaled (i.e. either enlarged or reduced). While this may be acceptable for most copy operations, there do exist situations where it would be desirable to have the copy different from the original. For example, when a single spaced document has been received for review and comment, it may be helpful to have room to write comments, corrections or other annotations between the lines. Conversely, when a multiple page document to be copied has excessive unused space, it may be desirable to remove the unused space and combine pages.
Performing such functions would be difficult using conventional light lens copying techniques. However, reproduction systems (e.g. digital copiers) that scan a document to convert it to a digital form prior to printing provide a base platform for such capabilities. One such system is described in U.S. Pat. No. 4,302,782 entitled "Reproduction Scanning System Having Intermediate Storage Between Input and Output Scanning Stations" (hereinafter the '782 patent). The '782 patent describes a reproduction system which utilizes optical scanning technology to obtain a document image, which is stored in an intermediate storage prior to transmittal to an output scanning station for printing. The system of the '782 patent may be used to magnify and enlarge source images. However, the '782 patent does not suggest any manipulation of image data stored in the intermediate storage.
Analysis of bit-mapped representations of text data is well known. Optical Character Recognition (OCR) is used to analyze bit-mapped representations of text data in order to translate into some character coding scheme (e.g. ASCII codes). OCR techniques typically require the segmentation of the bit-mapped representation into units such as paragraphs, lines of text and character blocks. The actual recognition is performed on the character blocks. OCR allows the resulting text to then be edited and used in commercially available word processing programs. OCR programs when used in combination with word processing programs could be used to perform the functionality of creating single or double spaced copies. However, OCR programs requires extensive processing time and do not preserve images (e.g. illustrations or photographs), handwritten marks or other non-text markings that may be on the original medium would require a great deal of processing time and would be impractical to implement on a reprographic device.
EP-A 434,930, Bagley et al. entitled "Editing Text In An Image" describes a system for editing text on the bit-mapped representations without the need to covert characters to codes. The system described in EP-A 434,930 is premised on manipulating text and does not disclose a technique for single or double spacing. Further, the system described is for use as an interactive editor when viewing the contents of the bit-mapped representation on a computer screen, rather than as a function on a copier or other reprographic device.
Reformatting of text based on a bit-mapped representation of an image is described in EP 0 585 073 A2, Card entitled "Automatically Changing Text Characteristics By Repositioning Word Images". In EP 0 585 073 A2, first image data is changed according to change data indicating the desired changes to the text. The technique described in EP 0 585 073 A2 operates on word images which may be inefficient for the application of the present invention and does not preserve images (e.g. illustrations or photographs), handwritten marks or other non-text markings that may be on the original medium.
The prior art does not teach or suggest providing automatic adjustment of the spacing between lines of text based on an analysis of the bit mapped representation of the text. Thus, it would be desirable to provide a copying system which is capable of efficiently creating double or single spaced copies and which preserves images, handwritten marks and other non-text markings on the original medium.